1. Field of the Invention
The present invention relates to paper loaders for an electrophotographic apparatus and, more specifically, to a controlling device for a pick-up roller.
2. Background Art
An electrophotographic image forming apparatus, such as a copier, a printer, a laser beam printer, or a facsimile, prints an image onto a sheet of paper that is loaded into the apparatus from a paper cassette that contains a stack of paper. To sequentially feed the sheets of paper from the paper cassette a sheet feeding device is used.
A sheet feeding device may be constructed using a pickup roller, also referred to as a roller, that sequentially feeds the top sheet of paper from a paper cassette into an electrophotographic apparatus. A rubber layer may be mounted on the outer surface of the pickup roller to increase the frictional interaction between the paper and the roller. The central axle is fixed to a frame. A pickup gear is installed at one end of the central axle to receive power that is then transmitted to the central axle. A bushing is fixed to the central axle and facing the pickup gear.
One method of controlling the feeding operation is to use a clutch spring to transmit the driving force that is transferred from a motor to the outer surface of a hub of the pickup gear. The force is then transferred to the outer surface of a hub of the bushing that is attached to the central axle.
Other techniques for modulating rollers are shown, for example, in U.S. Pat. No. 5,318,631 to Tsukamoto entitled Pressure Control Device for a Pressure Roller, U.S. Pat. No. 4,734,806 to Komatsu entitled Cam Plate for Positioning Head Base and Pinch Roller in Tape Player, and U.S. Pat. No. 4,236,660 entitled Solenoid Clutch Mechanism. The contemporary art does not provide a roller control device that is able to control the feeding of paper, that sets paper prior to feeding, and that is economical to produce.
As such, I believe it may be possible to improve on the prior art by providing a roller control device that does not require an additional sheet setting mechanism, that controls the feeding of sheets into an electrophotographic apparatus, that is usable in a compact apparatus, that is economical to manufacture, and that is easy to repair and maintain.